Pump for proportioning device

ABSTRACT

A RECIPROCATING PUMP WHICH HAS A ZERO TO NEGATIVE CLEARANCE WITH A VALVE SERVING AS A CYLINDER HEAD AND THE CONSTRUCTION THEREOF WHEREIN THE SLIDING RELATION HAS A LOW FRICTIONAL COEFFICIENT WITH A PISTON HEAD OF PLASTIC MATERIAL ENGAGING IN SEALED RELATIONSHIP A SLEEVE INSERT MADE PREFERABLY OF GLAZED CERAMIC TUBULAR SECTIONS WHICH IS READILY ASSEMBLED IN PLACE IN A PLASTIC SUPPORT BY A THREADED ELEMENT RECEIVED IN GROUPS OF SEGMENTED THREADS, AND METHOD FOR CUTTING ALL OF SAME SIMULTANEOUSLY.

Jan. 19, 1971 v. HECHLER IV 3,556,639

. PUMP FOR PROPORTIONING DEVICE v Filed March 5. 1969 I 2 Sheets-Sheet 10/ 3 I02 I oo 4 I I08 7 34 I04 92 TI -94 v INVENTOR VALENTINE HECHLER IVV/M7/w M Attorneys Jan. 19, MM v. HECHLER IV PUMP FOR PROPORTIONINGDEVICE I 2 Sheets-Sheet 2 Filed March 5, 1969 //VVENTOR VALE/VT/NEHECHLEI? ll/ y Attorneys United States Patent US. Cl. 417-435 11 ClaimsABSTRACT OF THE DISCLOSURE A reciprocating pump which has a zero tonegative clearance with a valve serving as a cylinder head and theconstruction thereof wherein the sliding relation has a low frictionalcoefiicient with a piston head of plastic material engaging in sealedrelationship a sleeve insert made preferably of glazed ceramic tubularsections which is readily assembled in place in a plastic support by athreaded element received in groups of segmented threads, and method forcutting all of same simultaneously.

CROSS REFERENCES This application contains divisible subject matter andis a continuation-in-part of application Ser. No. 520,568, filed Jan.14, 1966, hereby expressly incorporated by reference herein; andapplication Ser. No. 625,086, filed Mar. 22, 1967.

BACKGROUND OF THE INVENTION This application is a continuation-in-partof and an improvement over the pump structure shown in thecrossreference applications in that it eliminates the damage occurringwith plastic or metal cylinder walls when pumping liquid with suspendedabrasive particles in it. Moreover, cylinder sleeves can be readilymounted and readily interchanged with regards to various sizes ofpistons if a dilferent output rate is desired in some applications witha plastic retainer fastening means adapted to hold the ceramic sleeve inworking position.

More particularly in this respect the present invention further providesa weight reducing recess in a movable part that reciprocates thecylinder element. The recess is adjacent to a valved exhaust passage ina blind cavity defined by ribs which receive the sleeve whereby aretainer can be easily and releasably mounted in the recess to hold thecylinder sleeve in operative position. The cavity is so formed that allof the screw retaining threads can be out easily in segments with a 180movement of a'thread cutter to receive the shank of a threaded screwwhose flange overlaps a wall portion of the sleeve to hold it in itsworking position.

Another object of the invention is to provide motor and pump parts whichhave a low coefiicient of friction, employ inexpensive but efficientseals and valves for the working pump parts and if desired to furtherlubricate the flow and the parts with a polyalkylene oxide such aspolyethylene oxide in the concentrate to minimize the pump working loadupon the motor.

A further object of the invention is to provide a limited contact areafor'the concentrate in the pump which can be flushed clean in secondsfor or by another chemical concentrate entering the pump, and which whenstarted, automatically primes itself and prevents any vapor lock thatmight otherwise develop in the system.

A further object of the invention is to rapidly prime a reciprocatingpump by evacuating and compressing air to a pressure greater than theback pressure on a spring loaded exhaust valve and positively exhaustingthe compressed air through the valve against the elfort of the spring tohold the valve closed by making the exhaust ice valve at least a part ofthe cylinder head and positively engaging and displacing the headoutwardly by the piston at a terminal portion of its stroke.

These being among the objects of the invention, other and furtherobjects will become apparent from the description and claims including asimplified design and structure for ease of assembly, testing,installation, operation and servicing.

IN THE DRAWINGS FIG. 1 is a diagrammatical picture View of the deviceembodying the invention used for lawn care;

FIG. 2 is an enlarged longitudinally sectional view in the plane of theaxes of the pistons of the pump and motor arrangement embodying theinvention as the pump piston approaches the end of its compressionstroke or after it begins its intake stroke;

FIG. 3 is a view similar to FIG. 2 showing the pump piston and cylinderhead at the end of the compression stroke;

FIG. 4 is a top plan view of the motor piston showing the orientationand securement of the pump cylinder with a screw;

FIG. 5 is a perspective view of the reciprocating motorpump member ofthe invention for mixing concentrate in diluent in exact proportions;

FIGS. 6 and 7 are sectional views taken on lines 6 and 7 in FIGS. 2 and4, respectively; and

FIGS. 8 and 9 show the apparatus and a two-stop method of cutting a fulllength thread with 180 rotation of a double land top to receive a screwfor holding the pump cylindrical sleeve in place.

As more particularly described in the cross reference applications,diluent, such as water, flowing under pressure actuates a motor havingflow responsive motor pistons which in turn operate pumps having pumppistons to aspirate and inject exact portions of concentrate, such assuspension mixture of fertilizer, into the diluent that put of thediluent and exhaust of the concentrate occur simultaneously forprogressive mixing in the motor cylinder intimately and directly on eachexhaust stroke. Each pump is provided with tandem self-closing outputand intake pump valves which interengage at the end of the pumpcompression stroke and otherwise provide a double closure against thebackfiow of concentrate to prevent flow of diluent into the concentrateintake passageway.

Referring now to the drawings in further detail an application of theinventive concept is demonstrated at 10 in FIG. 1 as used at either endof a garden hose 12 and is supplied with municipal water from a valvedwater tap 14 of a building 15 preferably through a short section of hose11. Concentrate is drawn from an open or closed container 16 (FIG. 1). Aspray wand 18 with a quick shut-off valve 19 is shown with a fan spraynozzle 20 to spray the mixture on lawn 22. The concentrate in container16 can be a fertilizer with or without growth or selective plant controladditives or for pest control solutions or suspensions. In place of thenozzle 20 shown in FIG. 1 an earth penetrating lance may be used fortree root feeding. The short length of hose 11 is preferably employedbetween the device 10 and the house to yield to lateral hose strains andeliminate any sound conduction to the building 'water pipe system. Asdescribed in said application Ser. No. 625,086 means is provided asindicated at 21 for controlling the flow of diluent selectively with orwithout concentrate.

Reference is made to said reference applications for the operation ofthe device as a motor. Suffice to say in this connection that two motorpiston units (FIGS. 2 and 5) each having two heads 32, reciprocate inopposing motor cylinders 34 (FIGS. 2 and 3) under the force of waterflowing under pressure, such as municipal water pressure. Each unit iscontrolled by motor valves (not shown) that are actuated by push andpull rods 36 and 38, respectively, that are formed integrally with anidentical companion motor piston unit (not shown) which inturnisreciprocably controlled by the motor piston unit shown. Each motorcylinder 34 has a head 40 having a cross head concentrate intakemanifold 42 (FIG. 2) supplying hollow pump pistons 44. Each pump pistonis formed integrally with its respective cylinder head 40 and projectsinto the motor cylinder space 41. The manifold 42 supplies the pumppistons 44 with concentrate received from the container 16 after theyare primed The pump pistons extend into the respective motor cylinders adistance suflicient to cooperate with the motor pistons 32 throughouttheir excursion and the motor pistons in turn are cored out with ribbedblind holes 48 to receive a pump cylinder sleeve 76 that cooperates withthe pump piston 44 as will now be described.

As more particularly shown in FIGS. 4 through 9, the piston 30 of moldedplastic is cored out and lightened wherever possible for low inertia andhigh acceleration in its action. At opposite ends the motor pistons areprovided with two axially spaced circular flanges 50 providing anannular groove 52 between them receiving an elastomer chevron seal 54(FIG. 2) with its marginal V flanges 56 directed towards the cylinderhead 40. The interconnecting mid portion 58 (FIG. 5) of the piston headsis reduced in size and flattened at 60 very close to the axial centerthereof with corner brace portions 62 supporting the head portion.

I The two elongated blind holes 48 are cored in the piston head portionand extend into the mid portion with a segmented wall therebetweenforming two segments 66 with parallel facing edges 64 spacedapproximately the same distance as the remote walls 68 of the two holes48 to a predetermined depth. At this depth the segmented walls 66 areoffset towards each other to provide shoulders 70 below which thebottoms of the blind holes are recessed as at 72 to receive a spring.

' A shallow recess 74 adjacent to the inner one of the walls 68cross-sectionally defines a segment of a circle. As shown in FIGS. 8 and9, the opposite walls of the recess 74 are threaded at their widestspacing as at 78 by a threading tool 80 having diametrically oppositelands 82 whereby the flutes 84 are inserted full depth into the recessbetween facing the walls 76 (FIG. 8) and the tool is turned 180clockwise (FIG. 9) to cut the threads all at once and then remove toreceive screw 86 (FIG. 7) having a wrench receiving opening 88. Thisrelationship is one in which the major dimension of the recess in itslongest portion of its cross-sectional shape is greater than the crestdiameter of the threads and the minor dimension normal to the majordimension is less than the crest diameter of the threads. Accordingly,the threads of each segment taper in their height from their mid pointand the length of their root are over twice their maximum crest heightwhereby a threaded mating member is easily started in its threadedrelationship therewith.

The cored-out holes 64 receive a pump cylindrical ceramic sleeve 76therein having heat glazed inner and outer surfaces rounded at theirinner rim edge 71 where they rest on shoulders 70 while extending veryslightly above the face of the piston at the other end. The outsidediameter of the sleeve preferably is received with slight radiallooseness between the edges 64 of the segmented wall portions 66 and theremote walls 68. The reprises an externally conical elastomer washer 92(FIGJ' piston seals against metal.

Air or concentrate is ingested lnto the..cylinder sleeve maining area ofthe blind holes 48 serve as an exhaust passage 67 back to the face'69 ofthe piston heads.

-A disc is disposed at the inner end of the cylinder sleeve 76 tocooperate therewith in a dual capacity of a cylinder head and pumpoutput check valve that normally closes against the inner endthereof-under the influence of a light compression spring 98. The disccom- 3) and a rivet element 94 securing it to a washer 96 whose outeredge is received in guided relation by the ribsbelow the shoulders 70upon which the sleeve rests.-

A compression spring 98 bottoming inthe recess72' urges the disc toclosed position with the margins of the elastomer washer 92 engaging therounded rim edge 71 of the sleeve 76. Preferably the spring 98 isconical so that it can flatten when fully compressed when the disc valveopens.

A flanged sleeve member 100 is press fitted into the end of the sleevepiston 44 and is provided with an internal shoulder 102 at the inner endthereof to help support the pump intake check valve 104. The disc-likevalvef element 104 closes against the end 105 of the sleeve member as aninlet valve and is urged in that direction by an involuted compressionspring'106 interengaging cooperates as a pump seal with the glazed innerwall of the plastic sleeve cylinder 76 which surprisingly reduces toless than a third of the friction and wear of resilient 76 through theinlet valve 104 on the retracting movement of the pump piston 44 forsubstantially the full movement thereof and then is forced out therefrominto the motor cylinder 34 through the outlet valve 90 and exhaustpassage 68 around the sleeve cylinder 76 as the motor piston 30 advancesto exhaust diluent ahead of it. Thus, concentrate is injected in exactproportions into the motor cylinder and intimately mixed with eachdischarge of diluent by the motor pistons.

It will be appreciated that water under back pressure also assists inclosing exhaust valve 90 and it is to be noted that as each pump piston44 reaches the end of its movement (FIG. 3) the intake valve 104 engagesand positively opens the outlet valve 90 enough to release anycompressed air that may be trapped between them and thereby assures aquick and full prime, otherwise there being a substantial back pressureof diluent against the outlet valve 90 a full evacuation of such airmight be inhibited. This is significant since the concentrates arechanged from time to time with air in their containers and full primingimmediately is desirable with the first couple of strokes of the motorpiston for quick and accurate proportioning with changed concentrates.Otherwise, air drawn from the container could expand and contractendlessly in the pump cylinder 76 without the outlet valve 90 openingunder high diluent back pressures. Accordingly, the assured discharge ofentrapped gas each stroke is replaced by some concentrate intake andwithin two to four strokes of each of the four pistons, an otherwise airbound pump is fully primed. Thereafter, the pump is capable of liftingconcentrate a substantial distance by developing a partial vacuum ornegative gauge pressure as low as 3 lbs. per square inch, absolute,without changing the resulting output volume of the concentrate eachstroke.

Having thus set forth the objects and described a pre ferred embodimentof the invention with its novel arrangement of parts and resultsattained, it will be seen tion, the scope of which is commensurate withthe ap.- pended claims.

What is claimed is: 1. A self priming reciprocating pump for liquidscomprising a body including a pump cylinder means for one fluid with anopen exhaust end and having an exhaust space therebeyond, an exhaustvalve means reciprocable in said space to engage said open end forclosing and opening said open end, means including a second fluid underpressure in said exhaust space urging said exhaust valve to close saidopen end, piston means reciprocably mounted in said cylinder, meansincluding said second fluid for reciprocating said piston means andcylinder means with respect to each other with a negative clearancebetween the piston and the valve means at the end of the exhaust strokeof their relative reciprocation.

2. In a device of the class described, a self-priming pump for one fluidcomprising a pump cylinder having a movable head externally subjected toa liquid under a gauge pressure, piston .means in said cylinder. meansfor reciprocating said piston and cylinder with respect to each otherincluding said liquid under gauge pressure with an end stroke clearanceof substantially zero to negative clearance between the piston head andthe cylinder head at the end of their compression stroke.

3. The combination called for in claim I in which said piston has aninlet passage therethrough opening as a' valve port at its head end, aninlet valve admitting said one fluid and closing said valve port upon acompression stroke, said cylinder having an open end with said headconstituting a valve member closing under said gauge pressure againstthe open end of said cylinder upon the intake stroke of said piston.

4. In a device of the class described, a housing having an inlet openingfor receiving municipal water from a dwelling faucet, means insaidhousing actuated by said water and including a motor piston carryinga pump cylinder having a movable head and piston pump means for pumpinga second liquid and displacing said movable head to open it at the endof each compression stroke.

5. The device defined in claim 4 including a flexible conduit meansinterconnecting said inlet opening and said faucet with the housing independing relationship.

6. A pump for liquids including a blind cavity with longitudinal ribmeans on its wall portion, cylindrical sleeve received in said cavity'assupported by said rib means to define therewith fluted exhaust passages,shoulder means on said rib meanssupporting the inner end of said sleeve,exhaust valve means guided by said ribs beyond said shouldersforcooperation with the exhaust end 6 of the sleeve, resilient meansurgingsaid valve means to close against the exhaust end of the sleeve,piston means reciprocable in said sleeve having a negative clearanceatone end with the valve means on is exhaust stroke, andretainer means forsecuring said sleeve in place against said shoulders, said exhaustpassages interconnecting the exhaust end of the sleeve and acontractible space surrounding the opposite end of said piston means.

7. The combination called for in claim 6 in which said sleeve is made ofceramic heat glazed internally and provided at its exhaust end with aglazed rounded rim, and said piston includes an elastomer seal slidablyengaging said sleeve internally.

8. The combination in claim 6 in which said piston means is hollowdefining an inlet passage and includes an inlet valve atits inner end,spring means in said inlet passage supporting said valve and urging sameto its closed position.

Cit

9. The combination called for in claim 6 in which said body has athreaded wall portion defining a recess adjacent to the blind cavitywith a major dimension greater than the crest diameter of the threadsand a minor dimension less than the crest diameter of the threads saidthreads being segmented in groups in which the angular length of theroot of each thread is differentfrom the crest length of full threadheight for easeof starting the threaded engagement therewith of saidretainer means having a continuous" mating helical thread and a flangeportion securing said sleeve in place.

10. The method of priming a liquid pump cylinder havinga movablecylinder head portion including compressing on the compression cycles ofthe pump any compressible fluid present in the pump cylinder, andphysically discharging from the cylinder quantities of the compressedfluid under gauge pressure along with liquid present in the cylinderinto a liquid under gauge pressure by physically displacing said portionof the head at the ends of a succession of compression cycles toevacuate the compressible fluid from the ,cylinder.

11. The method called for in claim 10 in which said displacement isaccelerated incyclic movement towards the end of its exhaust stroke whencontacting said head portion.

References Cited UNITED STATES PATENTS 2,481,183 9/1949 Welby 1o3--2032,761,391 9/1956 Johnston' 103 3s 2,768,587 10/1956 Corneil 103 l66.5ROBERT M. WALKER, Primary Examiner

